Search results

1 – 2 of 2
To view the access options for this content please click here
Article

S. Abolfazl Mokhtari and Mehdi Sabzehparvar

The paper aims to present an innovative method for identification of flight modes in the spin maneuver, which is highly nonlinear and coupled dynamic.

Abstract

Purpose

The paper aims to present an innovative method for identification of flight modes in the spin maneuver, which is highly nonlinear and coupled dynamic.

Design/methodology/approach

To fix the mode mixing problem which is mostly happen in the EMD algorithm, the authors focused on the proposal of an optimized ensemble empirical mode decomposition (OEEMD) algorithm for processing of the flight complex signals that originate from FDR. There are two improvements with the OEEMD respect to the EEMD. First, this algorithm is able to make a precise reconstruction of the original signal. The second improvement is that the OEEMD performs the task of signal decomposition with fewer iterations and so with less complexity order rather than the competitor approaches.

Findings

By applying the OEEMD algorithm to the spin flight parameter signals, flight modes extracted, then with using systematic technique, flight modes characteristics are obtained. The results indicate that there are some non-standard modes in the nonlinear region due to couplings between the longitudinal and lateral motions.

Practical implications

Application of the proposed method to the spin flight test data may result accurate identification of nonlinear dynamics with high coupling in this regime.

Originality/value

First, to fix the mode mixing problem in EMD, an optimized ensemble empirical mode decomposition algorithm is introduced, which disturbed the original signal with a sort of white Gaussian noise, and by using white noise statistical characteristics the OEEMD fix the mode mixing problem with high precision and fewer calculations. Second, by applying the OEEMD to the flight output signals and with using the systematic method, flight mode characteristics which is very important in the simulation and controller designing are obtained.

Details

Aircraft Engineering and Aerospace Technology, vol. 91 no. 4
Type: Research Article
ISSN: 1748-8842

Keywords

To view the access options for this content please click here
Article

Kamran Raissi, Mahmoud Mani, Mehdi Sabzehparvar and Hooyar Ghaffari

This paper aims to investigate the addition of airdrop capability to a commuter aircraft and its consequences on the reversible flight control system.

Abstract

Purpose

This paper aims to investigate the addition of airdrop capability to a commuter aircraft and its consequences on the reversible flight control system.

Design/methodology/approach

Airdrop was modeled to include its effect on aerodynamics and flight control system. A mathematical model was also developed for the reversible longitudinal flight control system of a regional commuter aircraft using the available geometry, mass property and kinematics. The model was incorporated into a general multi‐body dynamics code and validated using existing manufacturer's data which included recorded data from flight. The airdrop simulation results showed that the flight control system is affected in two steps. In the first step, the movement of the load required a forward force by the pilot. In this step, the elevator power was a key factor and had to be increased to allow the pilot to keep the aircraft in trim position during the airdrop. In the second step, a sudden forward shift of centre of gravity required an abrupt change in the direction of applied force. The maximum allowable force and control column movement had to be checked. In the case under study, they did not impose any difficulty.

Findings

The result showed that a special consideration had to be taken into account when an aircraft with reversible flight control system was to be used for airdrop mission.

Originality/value

This paper investigates the behaviour of a reversible flight control system during airdrop operation through analysis and simulation.

Details

Aircraft Engineering and Aerospace Technology, vol. 80 no. 4
Type: Research Article
ISSN: 0002-2667

Keywords

1 – 2 of 2